Container



Oct. 5, 1965 N. A. LEWIS ETAL CONTAINER Filed April l5, 1963 INVENTOR.NATHANIEL A. LEWIS BY THOMAS E. K|RBY,JR.

United States Patent O 3,209,977 CONTAINER Nathaniel A. Lewis, HenricoCounty, and riliomas E.

Kirby, Ir., Chesterfield County, Va., assignors to Reynolds MetalsCompany, Richmond, Va., a corporation of Delaware Filed Apr. 15, 1963,Ser. No. 273,049 9 Claims. (Cl. 229-35) The invention relates to a novelimproved water soluble container adapted to release its contents whenimmersed in water. More particularly, the invention concerns a watersoluble plastic bag having at least one seam through which it is adaptedto release its contents, said seam being interiorly resistant to theaction ot wet contents of the bag.

Water soluble exible containers adapted to release their contents whenimmersed in water having a temperature up to about 100 F. and which aresubstantially soluble in hot water have been described in copendingapplication of Gnittin Serial No. 219,833, tiled August 28, 1962,entitled Flexible Packaging System. Such containers are especiallysuitable for use as hospital laundry bags, diaper bags, and the like. ltis known that the soiled laundry for which these types of bags are used,including hospital bed linens, garments, towels, and similar articles,is contaminated with pathogenic organisms. Prevailing practice inhospitals and homes involves placing soiled laundry in cloth bags, whichare porous and permit the escape of bacteria through the bag Walls.During the handling of cloth bags via laundry chutes and other means oftransportation, pathogenic bacteria are disseminated by currents ofmoving air, finding their way into clean linen supplies, food utensils,personnel uniforms, buildings and equipment, and creating seriousproblems of infection spread and control. Proposals to reduce thesehazards by employing bags made of impervious and insoluble bags made ofplastic films such as polyethylene, have been ineffective becausebacteria are spread when the contents are dumped out into the washingmachines, and because the disposal of the bags by incineration itselfpresents problems.

One form of water soluble flexible container which has been proposedcomprises oppo-sing panels of hot water soluble flexible plasticmaterial, with a layer of cold water sensitive plastic materialinterposed between said panels in position to be contacted by water whenthe container lis immersed in the water, the panels and the interposedplastic layer being bonded .to form a seam portion of the container, andthe plastic layer being readily softened by water at a temperature up toabout 100 F. to eiiect release of the seam. Thus, for example, twosheets of hot water soluble flexible plastic materials may besuperimposed .to define a hollow body portion of the container when thecontainer is distended, with a tape of cold water sensitive plasticinterposed between the sheets adjacent a longitudinal edge, the sheetsand the interposed tape being bonded to form a seam. The top margins ofthe sheets are left separable to provide an opening for filling thecontainer, while the sheets are bonded directly at their remaining edgemargins, as by heat sealing.

A bag of the type described is well suited for holding dry soiledlinens, as well as damp or wet linens. The latter may be at body.temperature or colder. Hospital laundry practice employs initialrinsing steps which are carried out with water at body temperature orcolder in order to loo-sen and flush away stains from blood and bodydischarges. This is followed by a hot water wash involving sudsingcycles with detergents and bleaches at temperatures customarily aboveabout 145 F., and Water lCe rinses. The Water soluble laundry bag isdissolved completely by the hot Water and passes into the waste disposalsystem.

During periods of heavy flow of soiled articles, which may be damp orwet, circumstances may necessitate the storage of soluble bags of thetype described containing wet linens for extended times until thelaundering facilities and equipment become available. Under theseconditions it is desirable to provide a container structure whereby thecold-water releasable portions of the bag seam or seams are protectedfrom contact with any moisture emanating from the contents duringperi-ods of storage, so that the contents may not be prematurelyreleased.

In accordance with the invention, a water soluble laundry bag isprovided which will hold wet linens indeiinitely at body temperature orcolder, and permit these linens to be contacted almost immediately bythe cold Water flush when the bag and its contents are placed in awashing machine, by release through at least one cold-water separableseam thereof, said seam being interiorly resistant to the action of wetcontents of the bag. The release seam is protected against the action ofmoisture emanating from the wet contents so that premature release ofthe contents, such as upon prolonged storage of the bag and contents,does not occur. When the bag and contents are exposed to a cold waterflush in the washing machine, .the contents are exposed through thereleased seam or seams to the action of blood and stain removing coldwater ushes in the machine; subsequently when hot water containingdetergents, soaps, bleaches and the like is added, the laundry bag willdissolve entirely and be disposed `of in the Waste waters from themachine.

These and other objects, advantages and details Will become apparent asthe description proceeds, and from the accompanying drawings, in whichFIGURE 1 is a perspective view of one embodiment of a laundry bagconstructed in accordance with the invention;

FIGURE 2 is a section taken on the line 7-7 of FIG- URE l, showing adetail of the side seam;

FIGURE 3 is a perspective view of another embodiment of the invention;

FIGURE 4 is a section taken on the line S- of FIG- URE 3, showing adetail of the side seam;

The container 1 is formed from a pair of superimposed hot Water solubleplastic sheets 2 of generally rectangular configuration. In theembodiment illustrated in FIG- URE l, the bag is provided with at leastone releasable seam 3. The seam structure corresponding to theernbodirnent of FIGURE l is shown in more detail in FIG- URE 2, whichillustrates the overlapping junction of panels 2 and an externallydisposed cold water sensitive plastic layer or tape 4. The bag containsat least one releasable seam of the type shown in FIGURE 2, althoughboth longitudinal edges may be so constructed. The panels or sheets 2are bonded along their lower edges to form a bottom seam 5, as, forexample by heat sealing. The upper margins 6 of the panels are separableto provide an opening for lling the container. The embodiment depictedin FIGURE 3 has similar configuration, but the seam structure isdifferent and is shown in more detail in FIGURE 4. While the bags shownin FIGURES l and 3 are depicted as rectangular in shape, it will beunderstood n that they may be made in any desired shape. It Will beunderstood further that a generally tubular body may be provided with atleast one seam of the types shown in FIG- URES 2 and 4, and that suchseam may be transverse as well as longitudinal, and that the seam neednot extend completely to the bottom edge of the bag.

In the embodiment shown in FIGURES 1 and 2, the bag is formed by bendingor reversely folding a single continuous panel 7 of hot water solubleplastic film so that the folded longitudinal edge 8 thereof will enclosethe longitudinal edge portion 9 of the opposing panel 10 of the bag. Astrip or tape 4 of cold Water sensitive plastic material is applied soas to overlie the longitudinal edge of panel 7 and the adjacent portionof panel 10 thus forming a seam, the tape 4 adhering to and bridging theexterior of folded edge 8 and the portion of panel 10 adjacent theenclosed edge 9 thereof, The externally disposed tape portion 4 is thusprotected from contact with moisture or water which may be presentinside the bag, by virtue of the lap joint between the reversely foldededge 8 of sheet 7 and the edge 9 of sheet 10 received therein. If it isdesired to further protect the tape portion 4 against any possibleseepage of moisture from the interior of the bag, the overlapping fold Sand the panel edge 9 may have therebetween a thin layer of a suitablesealing compound 11, such as, for example, petroleum jelly. The enclosedlongitudinal edge portion 9 of panel 10 is substantially planar.

In the embodiment of FIGURES 3 and 4, the bag is formed by bending orreversely folding both panels 12 and 14 of the bag so that the foldedlongitudinal edge 13 of panel 12 will lap and enclose the oppositelydirected folded longitudinal edge 1S of panel 14, as shown in FIG- URE4. This construction provides a particularly moisture and water-tightseam. Here also a strip or tape 16 of cold water sensitive plasticmaterial is applied so as to overlie the longitudinal edge of the panel12 and the adjacent portion of panel 14, forming a seam therewith, thetape 16 overlapping the panel edge 13 and adhering to said edge and tothe body portion of panel 14 adjacent to the enclosed edge 15. The tape16 is thus also fully protected against access thereto of moisture orwater inside the bag by virtue of the double reverse lapped folds at 13and 1S. If desired a sealing compound as at 11 FIG. 2 may be applied, asmentioned previously, between edge 13 and panel 14, or between edge andpanel 12, or both.

In the embodiments shown in FIGURES l and 3, the bags are provided withtwo cold-water releasable longitudinal seams, but it will be understoodthat where only a single releasable seam is desired, the bags may eachbe formed by bending a single panel of hot water soluble film back uponitself and then joining the free edges along one margin in seams of thetype shown in either FIGURE 2 or 4, While the bottom bag margin is heatsealed at S.

The manufacture of the containers of the invention may be carried out inseveral ways. Thus, to make the embodiment shown in FIGURE 1, a sheet ofhot water soluble plastic film 7, of sufficient width to provide tworeversely folded edges 8 is positioned beneath a somewhat narrower sheet10 and fed into a suitable apparatus of conventional type whereby thelongitudinal edges 8 of sheet 7 are folded over to enclose thelongitudinal edges 9 of sheet 10. A sealing compound 11 may be appliedto edge portion 9 at the same time, if desired. The portions 8 and 9 arelightly pressed together at relatively low temperatures between about200 and about 300 F., preferably about 25 0 F., and the cold-watersoluble tape 4 is applied simultaneously by being moistened on its undersurface very slightly. The temperature and pressure of adhesion are justsuliicient to bond the body portions and the overlying tape, butinsufficient to create a heat seal, or to bond the body panel portionstogether. In accordance with another method of manufacture, a mandrel isinserted between the panel portions to keep them separated and to avoidsealing the body portions together; a heat seal is applied to bond thetape portion to the exterior edges.

It will be understood that in either embodiment, the bottoms of the bagsmay be heat sealed in accordance with conventional practice, or they maybe sealed with a suitable adhesive.

The containers of the invention, particularly laundry bags, have beentested in hospital applications and have been found to possess numerousadvantages not previously obtainable using known types of containers.Among these advantages are a significant reduction in the incidence ofairborne bacteria and other organisms. The filled bags can be droppedthrough multistoried laundry chutes without damage or loss of contents.The invention permits the use of a single type of bag for dry, damp, wetor soiled hospital linens, and reduces labor costs in the laundry byeliminating the unpacking steps previously required, and by speedingloading time of the washing machines. At the same time the new bags donot interfere with the use of the cold flush in the washing machines toeliminate setting of blood stains and the like, in accordance withstandard hospital procedure.

The laundry bags lof the invention may readily be filled by suspendingthem from a ring stand or even over the back of a chair. Wet or dryhospital linens may be in serted up to the normal capacity of the bag.The bag is then closed by gathering the throat and tying it with a coldwater soluble plastic tape. The bag is transported to the laundry roomon a cart or via a laundry chute. In the laundry r-oom the filled bag isthrown directly into the washing machine without being opened orloosened. In the wash wheel of the machine, the first flush of water atbody temperature or colder is introduced to avoid the setting of stainsfrom blood and other body discharges. This iirst hush acts upon the coldwater soluble tape at the throat of the bag and upon the seam tapes orlayers 4 of cold water sensitive plastic. The weakened tape and sideseams rupture under the impact of the wash load and the front and rearpanels fall apart, allowing the soiled linen contents to spill out intothe water. After several cold rinses, the hot water sudsing and rinsingcycles are performed, during which the entire laundry bag dissolves,including both the hot water soluble panel sheets and the cold watersoluble tapes, and is removed in the discharge from the washing machine.

The water sensitive flexible plastic material employed for thefabrication of containers in accordance with the presently preferredpractice of the invention is polyvinyl alcohol sheet or film, of varyingthickness, and of varying types, depending upon the water sensitivity orsolubility characteristics desired.

For the container panels, there are two film characteristics ofimportance: (a) hot water solubility, and (b) damp stability. Thecriterion of hot water solubility which has proven desirable is that thepanel must dissolve completely in 170 F. water within a period of 5minutes, with agitation. At the same time, the panel material must besubstantially insoluble in supply water. Accordingly, the expression hotwater soluble is used herein to designate materials which are soluble inwater at higher temperature but are substantially insoluble in water atabout F. or lower. Damp stability is deiined as the ability of the filmto maintain its integrity as a iilm while in contact with damp linens.

It has been found advantageous to prepare the hot water soluble panelmaterial from polyvinyl alcohol formulations which have a relatively lowglycerol content in order to reduce sensitivity to moisture. Generally,between about 10 and about 18 pounds of glycerol, and preferably betweenabout 13 and about 16 pounds of glycerol, per 100 pounds of resin, aredcsirably included in the formulation. Thus, there may be employed forthe bag panel material, polyvinyl alcohol film material having thegeneral range of hot water solubility desired, but with their dampstability controlled by the glycerol coutent.

The polyvinyl alcohol film to be used for the hot water soluble panelspreferably has the following characteristics:

Thickness 0.5- mils. Average yield 21,600 sq. in./lb./mil. Specificgravity lll-1.31. Tensile strength 6,000 p.s.i. (minimum). 100% modulus(force required to double the length) 2,500 p.s.i. (minimum). ElongationSOO-600%. Internal tear resistance 500 gm./mil (minimum). Heat sealing260 F., 510 sec. Flammability Slow burning.

The cold water sensitive polyvinyl alcohol which is used for tying tapeand for side seam sealing at 4 in accordance with the invention is onewhich tends to soften in cold water, although not necessarily todissolve completely. By cold water is meant water at a temperature up toabout 100 F. Thus, for practical purposes a suitable cold watersensitive tape or layer is one which will release the contents of thebag in cold Water in less than 2 minutes, preferably less than l minute.A suitable commercially available cold-water sensitive tape is ReynolonPVA/WS-13.

Cold water sensitive polyvinyl alcohol film or use as a seam materialand for binding the bag mouth preferably has the followingcharacteristics:

Thickness About 0.015 in. Average yield 21,600 sq. in./lb./ml. Specificgravity 1.21-1.31. Tensile strength 2,000 p.s.i. (minimum). 100% modulus(force required to double the length) 1,000 p.s.i. (minimum). ElongationZ50-600%. Internal tear resistance 200 gm./ml (minimum). Heat sealing300 F., l sec. Flammablity Slow burning.

Extensive evaluation of these laundry bags in actual hospital use hasdemonstrated their suitability in general, pediatrics and nursery wards.

While present preferred embodiments of the invention have beenillustrated and described, the invention may be otherwise variouslyembodied and practiced within the scope of the following claims.

What is claimed is:

1. A water soluble plastic lm laundry bag for holding wet linens at bodytemperature or colder and which releases its contents when immersed inwater having a temperature below about 100 F. and thereafter dissolvescompletely in hot water, comprising superimposed panels of hot watersoluble flexible plastic film having good damp stability, the topmargins of the panels being separable to provide. an opening for fillingthe bag, said panels having at least one releasable side seam portionalong one pair of marginal edges thereof comprising a longitudinal edgeof one panel reversely folded to enclose a longitudinal edge of theopposing panel and a layer of cold water sensitive plastic materialpositioned adjacent to said longitudinal edges and overlapping andadhering to the exterior of said folded edge and the body portion ofsaid opposing panel, said plastic layer being readily softened by waterat a temperature below about 100 F. to effect release of the seam, saidpanels being bonded together directly to form seams at their remainingedge margins.

2. The laundry bag of claim 1 in which the hot water soluble plasticfilm is polyvinyl alcohol.

S. The laundry bag of claim 1 in which the cold water sensitive plasticmaterial is cold water soluble polyvinyl alcohol.

4. A container for effecting self-release of contents therewithin whenimmersed in water comprising a pair of superimposed panels of flexiblematerial, said panels being connected along a plurality of edge marginst-o define a contents-receiving pocket, one of said connected edgemargins including a water releasable seam protected from inadvertentrelease by moisture internally of said container present in saidcontents, said releasable seam comprising a reversely-foldedlongitudinal marginal edge of one of said panels receiving within thefold thereof the adjacent marginal edge of the other of said panels toprevent moisture leakage therepast from interiorly of said container,

and a strip of water-sensitive plastic material disposed exteriorly ofsaid container in bridging overlying bonded relation to the reverselyfolded marginal edge of said one panel and the adjacent portion of saidother panel to secure'said panels together therealong,

said plastic strip having the characteristic of being readily softenedby water for easy rupture to effect release of the seam and discharge ofthe container contents therethrough. 5. A container for effectingself-release of contents therewithin when immersed in relatively coldWater comprising a pair of superimposed panels of flexible plasticmaterial soluble in hot water in excess of about F., said panels beingconnected along a plurality of edge margins to define acontents-receiving pocket,

one of said connected edge margins including a coldwater-releasable seamprotected from inadvertent release by moisture interiorly of saidcontainer present in said contents, said releasable seam comprising areversely-folded longitudinal marginal edge of one of said panelsreceiving within the fold thereof the adjacent marginal edge of theother of said panels to prevent moisture leakage therepast frominteriorly of said container,

and a strip of cold-water-sensitive plastic material disposed exteriorlyof said container in bridging overlying bonded relation to the reverselyfolded marginal edge of said one panel and the adjacent portion of saidother panel to secure said panels together therealong,

said plastic strip having the characteristic of being readily softenedby water for easy rupture at a temperature below about 100 F. to effectrelease of the seam and discharge of the container contentstherethrough.

6. The container of claim 5 in which the enclosed longitudinal edgeportion -of said other panel is substantially planar.

7. The container of claim 5 wherein said connected edge margins of saidpanels include a plurality of said cold-water releasable seams.

8. The container of claim 5 wherein said other panel marginal edge isreversely folded in a direction opposite to that of said one panel tofurther insure against moisture leakage therepast to the exterior of thecontainer.

9. The container of claim 5 wherein a sealing compound is providedbetween the lapping surfaces of said panel edge margins at saidreleasable seam.

References Cited by the Examiner UNITED STATES PATENTS 2,331,955 10/43Beebe et al 229-62 2,750,027 6/ 56 Cummings 206-65 FOREIGN PATENTS1,192,726 4/59 France.

THERON E. CONDON, Primary Examiner.

1. A WATER SOLUBLE PLASTIC FILM LAUNDRY BAG FOR HOLDING WET LINENS ATBODY TEMPERATURE OR COLDER AND WHICH RELEASES ITS CONTENTS WHEN IMMERSEDIN WATER HAVING A TEMPERATURE BELOW ABOUT 100*F. AND THEREAFTERDISSOLVES COMPLETELY IN HOT WATER, COMPRISING SUPERIMPOSED PANELS OF HOTWATER SOLUBLE FLEXIBLE PLASTIC FILM HAVING GOOD DAMP STABILITY, THE TOPMARGINS OF THE PANELS BEING SEPARABLE TO PROVIDE AN OPENING FOR FILLINGTHE BAG, SAID PANELS HAVING AT LEAST ONE RELEASABLE SIDE SEAM PORTIONALONG ONE PAIR OF MARGINAL EDGES THEREOF COMPRISING A LONGITUDINAL EDGEOF ONE PANEL REVERSELY FOLDED TO ENCLOSE A LONGITUDINAL EDGE OF THEOPPOSING PANEL AND A LAYER OF COLD WATER SENSITIVE PLASTIC MATERIALPOSITIONED ADJACENT TO SAID LONGITUDINAL EDGES AND OVERLAPPING ANDADHERING TO THE EXTERIOR OF SAID FOLDED EDGE AND THE BODY PORTION OFSAID OPPOSING PANEL, SAID PLASTIC LAYER BEING READILY SOFTENED BY WATERAT A TEMPERATURE BELOW ABOUT 100*F. TO EFFFECT RELEASE OF THE SEAM, SAIDPANELS BEING BONDED TOGETHER DIRECTLY TO FORM SEAMS AT THEIR REMAININGEDGE MARGINS.